HS: repeat property for-loops + where (+3 tests)

Re-applied from worktree-agent-a7c6dca2be5bbada0 (commit c4241d57)
onto HEAD that already has clusters 30, 26, 27 runtime changes —
straight cherry-pick conflicted on the cluster-30 log-all block
and cluster-27 intersection helper, so the logical diff was
replayed surgically.

Parser (parse-atom object-literal):
- obj-collect now `append`s pairs in source order instead of
  `cons`'ing, so `{foo:1, bar:2, baz:3}` reaches hs-make-object
  as `((foo 1) (bar 2) (baz 3))`.

Compiler (emit-for, array-index emission):
- emit-for detects `for x in COLL where COND` (parser wraps COLL
  as `(coll-where INNER COND)`) and rewrites the filter lambda
  to bind the for-loop variable name rather than the default
  `it`, so `where x.val > 10` sees the right binding. Also
  unwraps `coll-where` so filter targets the real inner coll.
- emit-for now wraps a symbol collection with `cek-try` (not the
  broken `hs-safe-call`, which has an uninitialised CEK call-ref
  in the WASM build) so `for prop in x` after `set x to {…}`
  iterates x's keys instead of nil.
- array-index emits `(hs-index obj key)` instead of
  `(nth obj key)`, which only worked on lists.

Runtime:
- New polymorphic `hs-index` dispatches to get / nth / host-get
  based on target type (dict / list / string / otherwise).
- `hs-put-at!` default branch now detects DOM elements via
  `hs-element?` and delegates to `hs-put!`, so `put X at end of
  elt` on a DOM node appends innerHTML instead of crashing.
- `hs-make-object` tracks insertion order in a hidden `_order`
  list; `hs-for-each` and `hs-coerce` (Keys / Entries / Map
  branches) prefer `_order` when present, filtering the marker
  out of output.

Suite hs-upstream-repeat: 25/30 → 28/30 (+3).
Smoke 0-195 unchanged at 165/195.

lib/hyperscript/parser.sx

@@ -244,7 +244,8 @@
                             ((value (cond ((= (tp-type) "local") (let ((v (tp-val))) (do (adv!) (cond ((= v "true") true) ((= v "false") false) ((= v "null") nil) (true (list (quote ref) v)))))) ((= (tp-type) "colon") (do (adv!) (parse-expr))) (true (parse-expr)))))
                             (do
                               (when (= (tp-type) "comma") (adv!))
-                              (obj-collect (cons (list key value) acc))))))))
+                              (obj-collect
+                                (append acc (list (list key value))))))))))
                   (list (quote object-literal) (obj-collect (list)))))
               ((and (= typ "op") (= val "\\"))
                 (do